An extension of the twinax based console is to use a PC with a twinax/5250 emulation card to connect via twinax as a physical console. You then have the possibility to use something like PCAnywhere to take control of the machine remotely.

Depending on your hardware the HMC will only run on Power 5 and Power 6 machines and up. This works very well for taking over the console from remote PCs and gives you a lot of flexiblity. It also allows you to configure and manage LPARs and OnDemand CPU and Memory features. For this newer hardware, the only way to go.

The older machines all have 3 options.
1) Twinaxe connected consoles. This is the most reliable and stable but also the least accessable.
2) Operations Console which is a PC directly tied to the unit via a serial cable but again it is limiting unless you use some remote access software like Dameware, PC Anywhere, etc.
3) LAN Console. This is the most flexible option as it allows you to create several backup console sessions if you loose the other one and you can easily take over the console as well as the control panel. This is extremely important when you need to IPL from the front control panel.